The present invention relates generally to the field of analytical instruments and more particularly to operating methods and techniques for such instruments.
Clinical analyzers are well known in the art for analyzing patient samples to determine the presence and/or concentrations of substances in such samples. The analyzers may be very simple, single analyte instruments that require many of the steps in an analysis to be performed by an operator. For example, the operator may be required to place the individual sample onto the analyzer, add reagents to the sample, time the reaction, and read a resulting value from the analyzer. The value would then be compared to calibration values by the operator to determine a final result, often in terms of analyte concentration in the patient sample.
The more sophisticated clinical analyzers generally perform many or most of these and other steps automatically. If an automated analyzer is dedicated to performing a limited number or menu of analyses for each sample, then the operator need only place patient samples onto the analyzer and start the analyzer operation. Other automated analyzers offer a menu of tests that may be performed for each sample, requiring that the operator specify the particular tests required.
Each automated analyzer can be considered as having a characteristic operating method. For example, some analyzers perform all tests requested for a sample before beginning the analysis of a next sample. Other analyzers treat each test requested for a sample individually, performing each such test as a separate subcycle of the overall operation of the analyzer. In such analyzers, there may be a number of tests in progress at any one time. Different tests may be simultaneously under way for one sample while the same tests may be in progress for several different samples. Analyzers of this latter type are often referred to as "random access" analyzers.
Every test or chemistry on an analyzer has its own particular requirements, including the reagents needed and the processing time for the test. Some tests use only one reagent, while other tests may require several reagents or the addition of a trigger reagent to begin a timed reaction sequence. The processing time may not be critical for some tests, with others requiring specified incubation and reaction times that must be precisely observed.
As the number of tests on the menu of a random access analyzer increases, the number of different requirements for such tests also increases. This added complexity affects the analyzer throughput, that is, the number of samples that the analyzer can process in a given time.
Thus there is a need for a random access clinical chemistry analyzer that can maximize throughput while retaining a large menu of available chemistries. There is also a need to provide an operating method for such an analyzer that provides sufficient variability and adaptability so that new chemistries can be added to the menu without requiring modification of the operating method or the analyzer itself.